Telecommunications is a rapidly changing field of technology. Consequently, the field of telecommunications is replete with prior art references that show advancements in most every piece of equipment associated with the telecommunications industry. The most noticeable advancements to the field of telecommunications may be those occurring to the simple telephone. In recent years, the telephone has undergone a transformation from a simple way to communicate to a far more sophisticated apparatus that utilizes multimedia technologies. With the advent of cellular telecommunications networks, portable telephones and car telephones have become commonplace. Similarly, with the advent of facsimile transmission technology, "fax" machines have become commonplace, as are telephones integrated with fax machines. However, telephones are no longer being considered just voice or facsimile transmitters and receivers. Rather, telephones are now being integrated into highly sophisticated portable computers, thereby transforming the simple telephone into a more versatile multimedia device. For instance, certain telephones are being manufactured with large display screens and sophisticated microprocessors that store and run complex software. As such, the person may use the device either as a telephone or as a personal computer, running any software currently available. Such software is capable of creating complex graphic images on the display screen of the device, wherein, with a few simple commands, the information on the display screen can be transmitted as a facsimile transmission. Similarly, any such prior art device can receive facsimile transmissions sent to it, via a cellar telecommunication network or a hard-wire telephone line interface. Such portable devices that are part telephone, part facsimile machine and part personal computer are sometimes referred to as personal digital assistants (PADs) an example of which is being sold by A.T.&T. under the mark EO 440 Personal Communicator. A listing and description of most commercially marketed portable handheld computer devices with pen-write screens is made in an article by Christopher Barr et al. entitled Pen Pals, PC Magazine Volume 12, Number 17 pgs. 116 et seq. (October 1993).
Although the innovations in telephone equipment technology result in a far more versatile and useful telecommunications tool, the products currently being produced do contain certain disadvantages. For instance, many prior art multimedia telephones require a special stylus to create graphic images on the electronic display of the device. As a result, there is no hard copy of what is being entered onto the electronic display. Consequently, to obtain a hard copy of what is shown on the display, the device must be either coupled to a printer or the information downloaded to a disk which must then be taken to another computer and printed. It is conceivable that such prior art multimedia devices may have the capacity to print directly on to paper, much in the same way that facsimile machines print onto paper. However, such multimedia devices are typically portable and lightweight. As a result, the ability to retain a removable amount of paper is limited, as is its ability to drive a high quality printing head.
In the prior art, the electronic display of many multimedia telephones are typically liquid crystal displays (LCDs). LCDs do not have a high degree of resolution. As a result, the graphical image produced on the LCD is often not clear. Additionally, very small details or text written in small fonts are often illegible when displayed on an LCD. As a result, if a complex document or blueprint is being viewed or faxed, important information may be lost by the deficiencies of the resolution in the screen. Another deficiency of LCDs is that the image they produce is typically distorted as the LCD is touched. Since the LCD is being written upon by a stylus, the pressure of the stylus may distort the image being displayed, thereby causing difficulties in producing graphical images of exacting detail.
Another problem with prior art multimedia telephones is that it only has a single screen. Many documents, facsimile transmissions and the like are several pages long. As a result, only one page at a time can be displayed. To produce hard copies of the pages, each page must be downloaded to a printer. Since multimedia telephones are portable, hard copies of the image on the electronic display can be made by photocopying the display. However, the LCD displays do not always provide a great contrast between the background and the image. Consequently, the photocopied image is not always clear. Additionally, although multimedia telephones are portable, they are far from flat. It is therefore difficult to properly place the display of such a device upon a photocopy machine.
The present invention provides improvements to the art of multimedia telephones by providing a tactile screen that enables a piece of paper to be placed over the screen and written upon by an ordinary pen or pencil. As a result, a simultaneous hard copy can be obtained on paper of what is being entered into the electronic display. Furthermore, the electronic display is not distorted by tactile pressure. Consequently, the pressure of a pen or pencil on the screen would not distort the image displayed. Electronic displays that utilize pads capable of being engaged by an ordinary pen or pencil are known in the art as exemplified by U.S. Pat. No. 4,963,8591. Parks entitled METHOD AND APPARATUS FOR CAPTURING INFORMATION IN DRAWING OR WRITING, and U.S. Pat. No. 4,980,646 to Zemel, entitled IMPEDANCE TOMOGRAPHIC TACTILE SENSOR. However, such tactile pads are not adapted for use with displays of a high resolution since the resolution of the tactile pad is typically far inferior to the resolution of the display, thereby adversely effecting the performance of the display. Furthermore, these tactile pads are not transparent and cannot be used over an electronic display.
It is therefore an object of the present invention to provide a multimedia telephone with a tactile pad that has a resolution that is at least as great as the resolution of the display itself. As such, the image produced on the display is not adversely affected by the resolution of the tactile pad being engaged.
It is a further object of the present invention to provide a multimedia telephone device with a removable electrophoretic display, wherein the display can be removed, photocopied and returned to the telephone without loss of the image on the display.